This invention relates to a multi-fuel engine control and particularly to such a control of the type in which fuel is pumped from a tank to the engine through a conduit which includes a fuel composition sensor, the output of which is used in updating a stored engine fuel control parameter. If the tank contains a mixture of gasoline and methanol, for example, in proportions which might vary with time, a fuel composition sensor which generates a signal indicative of the relative proportions of gasoline and methanol may be sampled to update the stored engine fuel control parameter, which is used by an engine operating computer in controlling the fuel supply system in order to provide the correct amount of fuel with varying fuel composition.
However, the fuel composition sensor may be placed in the conduit at a point between the fuel tank and the engine in which a predetermined time is required for the fuel pump to pump the fuel from the sensor to the engine. This may be true even if the sensor is located in the engine compartment itself. If fuel composition is changing slowly and gradually, the time delay between the sensing of a fuel change and the arrival of the changed fuel at the engine may be ignored. However, if a sudden significant change in fuel composition is sensed and the stored engine fuel control parameter is immediately updated in response to this change with unchanged fuel still in the conduit between the sensor and the engine, the engine will operate with the wrong fuel amount for the predetermined time.